He says there has been decades of studies on the psychological habits of shoppers. He says for some people, the idea of getting out in the middle of the shopping crowds stimulates certain parts of the brain, much like bungee jumping or skiing.

"It acts on our pleasure centers just like anything else just like any drug," Duber-Smith said. "For a lot of people, shopping is a drug. There are actually shopping addicts out there."

Hepburn would not call herself a shopping addict by any means. But, she does enjoy the adrenaline rush.

"It's just exciting to go early and get out with everybody," Hepburn said. "My sister-in-law says go knock elbows with everybody."

But, it is that same excitement that forces people to stay away from shopping on Black Friday.

"It frightens me," Carin Newell, a shopper at Park Meadows Mall, said. "I don't want to deal with all of the crazy fighting for stuff."

Duber-Smith says there's psychology in the numbers associated with sales, as well.

"Should you offer 25 percent off or $50 off?" Duber-Smith said. "The $50 number is higher. That resonates with the consumer. So, even if that's not a better deal with the consumer, consumers will still perceive it as a better deal."

Duber-Smith says make sure you do the math before you buy.

Hepburn says she always does.

"Definitely percentage off, things that are on sale that I was probably going to buy anyway," Hepburn said.

She says she likes achieving that feeling of shopping accomplishment on Black Friday.